We have been developed a support system to interactively search certain articles of users' interest on the World Wide Web (WWW) without their hesitating over query choices. Especially we have been implementing an effective application system to enable tourists to easily find special event information of their interest and to enjoy their own tours. This system also enables developers of each system to provide them with the means of easily constructing an initial database and automatically updating it.
As events are generally held cyclically, we have assumed events or keywords related to the events will appear in each term. If we can extract keywords that appear cyclically in a corpus including date information, we can obtain event keywords easily. The system can extract event information using the event keywords as queries for WWW information retrieval systems, and update the database automatically.
In this paper, we introduce our support system with a focus on a concept to extract event keywords and event information through the appearance of keywords periodically. We found our approach effective by some experiments.